基于Android平台的移动视频监控系统的研究

发布时间：2018-11-13 08:58

【摘要】：近年来,随着国民经济的不断发展,视频监控技术已经在政府、教育、娱乐、医疗、公共交通等众多领域得到了广泛的应用。传统的视频监控系统主要基于有线网络进行监控,具有系统布线复杂、铺设成本较高以及灵活性较差等缺点,无法满足人们随时随地进行监控的需求。随着无线网络技术的不断发展、智能手机硬件水平的不断提高,移动视频监控系统得以实现,并在实际应用中显示出极大的竞争优势。本文基于Android平台,对移动视频监控系统的实现过程进行研究。本文针对移动视频监控系统的视频编码、传输、组包、解码以及视频播放等环节进行了详细的介绍。首先,移动视频监控系统有别于传统的视频监控系统,需要通过无线网络进行数据传输。由于无线网络带宽有限且稳定性较差,’因此本系统采用图像压缩比率较高、网络适应性强的H.264编码标准进行编码。其次,在数据传输方面传统的方式是采用RTP协议与RTCP协议配合进行数据传输。由于这种传输方式实现较为复杂,因此本文采用一种自定义的通用消息头结构对视频数据进行传输,以降低数据传输的复杂度。然后,本系统为了提高视频监控的时效性,采用UDP协议作为系统传输层协议。由于UDP协议是不可靠传输协议,因此在数据传输过程中不可避免地会出现丢包的现象。系统对丢包现象进行了精细的处理,避免出现由于数据丢包造成的播放画面的花屏或卡顿的现象。再次,对于视频数据的解码过程,Android系统自带的多媒体处理控件OpenCore有被Stagefright取代的趋势,而Stagefright控件又有支持的文件格式较少且不稳定的缺点。与Android系统自带的多媒体处理引擎相比,FFmpeg具有跨平台、框架稳定、支持文件格式较多等优点,因此本系统采用FFmpeg对视频数据进行解码。本文对于FFmpeg的编译过程也进行了详细的讲解。最后,对于视频数据的播放,本系统分为历史视频数据和实时视频数据两种情况进行处理。系统将耗时的逻辑操作放入子线程中进行,避免了由于频繁地更新UI线程造成线程阻塞现象的发生。通过实践证明,本文提出的基于Android平台的移动视频监控系统,能够满足实际项目需求,具有较好的监控效果。
[Abstract]:In recent years, with the development of national economy, video surveillance technology has been widely used in many fields such as government, education, entertainment, medical treatment, public transportation and so on. The traditional video surveillance system is mainly based on wired network, which has the disadvantages of complex system wiring, high laying cost and poor flexibility, which can not meet the needs of people to monitor at any time and anywhere. With the development of wireless network technology and the improvement of smart phone hardware, the mobile video surveillance system has been realized, and has shown a great competitive advantage in practical applications. Based on Android platform, the realization process of mobile video surveillance system is studied in this paper. In this paper, video coding, transmission, packet formation, decoding and video playing of mobile video surveillance system are introduced in detail. Firstly, the mobile video surveillance system is different from the traditional video surveillance system, and it needs to transmit data through wireless network. Because the bandwidth of wireless network is limited and the stability is poor, this system adopts the H.264 coding standard which has high image compression ratio and strong network adaptability. Secondly, the traditional way of data transmission is to use RTP protocol and RTCP protocol for data transmission. Due to the complexity of this transmission mode, a custom universal header structure is used to transmit video data in order to reduce the complexity of data transmission. Then, in order to improve the timeliness of video surveillance, UDP protocol is adopted as the system transport layer protocol. Because UDP is an unreliable transport protocol, packet loss will inevitably occur in the process of data transmission. The system handles the phenomenon of packet loss carefully to avoid the phenomenon of display screen or Catton caused by data packet loss. Thirdly, for the decoding process of video data, the multimedia processing control OpenCore of Android system has the tendency to be replaced by Stagefright, while the Stagefright control has the disadvantage of less and unstable file format. Compared with the multimedia processing engine of Android system, FFmpeg has the advantages of cross-platform, stable frame and more supporting file formats. Therefore, the system uses FFmpeg to decode video data. The compilation process of FFmpeg is also explained in detail in this article. Finally, the system is divided into historical video data and real-time video data. The system puts the time-consuming logic operation into the child thread to avoid the thread blocking caused by the frequent updating of the UI thread. It is proved by practice that the mobile video surveillance system based on Android platform can meet the needs of the actual project and has a good monitoring effect.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN948.6

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